1. Technical Field
The present invention relates to a control system, a program, a method of controlling mechanical equipment, or the like.
2. Related Art
In work using a robot or the like, specific movements may be desired while not only locations but also forces are controlled. The force control may be used in the case where, for example, a soft object or a fragile object is handled without breakage, the case where an object surface having a complex shape is traced with a constant force, or other cases. In order to perform such force control, processing of detecting forces using a force sensor and incorporating magnitudes and directions of the forces into a control loop is necessary.
However, the force sensor detects not only external forces desired to be detected but also forces caused by the influences of finger structures attached thereto, forces from tools or work pieces grasped by the fingers, or the like. These forces are not constant, but change according to various conditions. Accordingly, it is difficult to separate the external forces desired to be detected and the forces from the finger structures and the tools or work pieces grasped by the fingers.
In this regard, JP-A-6-339885 discloses a technique for correcting a gyro effect due to a weight of the finger structures and its rotation. JP-A-6-339885 concerns the handling of a rotator such as perforating, burring, grinding, and polishing work using robots. Specifically, the moment that changes according to the arm position and the gyro effect generated by the rotator are corrected using the tool's center of gravity, the rotator's center of gravity, and the location of the contact point in the sensor coordinate system as given information, and a substantial external force is sensed.
Further, JP-A-2008-142810 discloses a technique for correcting the effect of centrifugal force or the like in addition to JP-A-6-339885. JP-A-2008-142810 corrects for the centrifugal force by the movement of the arm and correction processing is realized using the mass of the tool, location of the center of gravity, location of the arm, velocity, and acceleration detection units, and kinetic terms, in gravity computation units.
Furthermore, JP-A-2007-276112 discloses a technique for grasping and releasing an object by simply estimating an external force in the vertical direction rather than by the fine external force correction like JP-A-6-339885 and JP-A-2008-142810. JP-A-2007-276112 converts the force sensed by fingers from the hand coordinate system into the base coordinate system of the robot, and thereby, performs grasp control.
The techniques of JP-A-6-339885, JP-A-2008-142810 and JP-A-2007-276112 are based on the assumption that a physical model (for example, a weight distribution or the like) of a mechanical mechanism (including finger structures, or a tool grasped by the finger structures according to circumstances) are known. Accordingly, in the case where the physical model of the mechanical mechanism is unknown, the case where the physical model changes depending on the situation, or the like, it is difficult to appropriately correct for the influence on the force sense value by the mechanical mechanism (the detection value of the force sensor).